Since it's called 'emperor's domination', the emperor must be a central figure. There might also be his advisors or generals. Maybe there are some characters who oppose his rule, like rebel leaders or ambitious nobles that could also be important characters in the story.
There could be a loyal general. For example, in some stories, this general helps the emperor in battles and political maneuvers. They have a deep bond of trust and respect. The general is often highly skilled in warfare and has a strong sense of loyalty towards the emperor.
I'm not entirely sure as I haven't read it in detail. But generally, it might involve the story of an emperor, his rise to power, political intrigue, and battles perhaps.
I don't know the specific main characters in the 'abyss domination novel'. However, they could be adventurers who are drawn to the abyss for various reasons like seeking power or knowledge, or they might be native creatures of the abyss with extraordinary abilities who play a significant role in the story.
Maybe there is a female character who is either the emperor's love interest or a powerful sorceress who has some connection to the sword. She could be helping or hindering the emperor in his journey with the sword. And there could be an antagonist, perhaps a rival emperor or a dark lord who wants to take the sword for his own evil purposes.
Since I'm not acquainted with this light novel, we can only make some educated guesses. The emperor is surely a key character. There could be a young and ambitious person, perhaps a commoner who by some twist of fate ends up on the emperor's lap. This character would then be thrust into the complex world of the imperial court. There might also be antagonists, like jealous nobles or power - hungry ministers who oppose the main character's new - found position close to the emperor.
Typically, the main character is the emperor himself. He could be a young and inexperienced one at the start, like in 'The Novice Emperor's Journey' where the emperor has to learn how to rule while facing various threats.
The novels about the emperor were novels with the theme of the emperor. They usually described how a powerful emperor achieved his goals through power and conspiracy. These novels often involved political struggles, schemes, and revenge. Di Ba novels were very popular in Chinese literature. Some of the famous works included "Lord Snow Eagle","Empire","Di Ba" and so on.
It could be a powerful Pokemon like Mewtwo. Mewtwo has the strength and intelligence to potentially be a dominant force in such a fanfic.
The main character is of course the Magus Emperor himself. He is the central figure driving the story forward with his growth and adventures.
The main characters could include the Star Emperor's closest friends from his youth who now hold important positions in his empire. There may be a wise old sage who guides the Star Emperor in his decisions. Also, an enemy general from a rival star empire who is constantly plotting against the Star Emperor could be a major character. These characters would interact with the Star Emperor, creating a complex web of relationships, power plays, and storylines within the light novel.